Apparatus for molding pulp



Junfi 5, 9 H. KOLLMANN 2,748,672

APPARATUS FOR MOLDING PULP Filed May 14, 1952 2 Sheets-Sheet 1 IN V ENTOR.

J 6 H. KOLLMANN APPARATUS FOR MOLDING PULP 2 Sheets-Sheet 2 Filed May14, 1952 INVEN TOR. %/17 .i/Zwmwz fife/way United States PatentAPPARATUS FOR MOLDING PULP Harry Kollmann, Waubeka, Wis., assignor toFormart Containers, Incorporated, Cedarburg, Wis., a corporation ofWisconsin Application May 14, 1952, Serial No. 287,780

1 Claim. (Cl. 92-54) This invention relates generally to an improvedapparatus for molding pulp into .a particular shape, and especially toan improved machine for molding papier-mach vases.

Papier-mach vases, which are formed from a paper pulp, .have become'verypopular for displaying floral bouquets because of the desirablequalities of the material, and the inexpensiveness of the vases. Suchvases take the usual form in having a large opening at the top andtapering inwardly to the base 'which extends outwardly to providestability to the vase. Because the base and top opening are larger thanthe central portion of the vase it cannot be formed as-a unit on asingle mold since the mold could not be removed without destroying it.It has therefore been the general practice to provide a mold for thebody or upper portion of the vase upon which the paper pulp is formedand utilize a sand core for the base. The sand core is completelycovered with the paper pulp to form a separate base, which is secured tothe body portion of the vase to complete the unit, the sand core"becoming an integral part'of the vase.

The production of the sand core itself for use in manufacturing suchvases represents a substantial portion of the cost of the vase andconsiderable labor is involved in fabricating such a base containing asand core. In addition, since the sand becomes an integral althoughinvisible part of the vase, it greatly increases its weight, resultingin higher shipping costs, which is an important factor in the total costof an item of this nature.

It is therefore a general :object of the present invention to provide animproved apparatus for molding a papiermach vase in which the necessityof a sand core for the base is eliminated.

Another object is to provide an improved apparatus for molding the baseof a papier-mach vase integrally with its body.

Another object is to provide an improved apparatus for molding vases ofthe usual configuration from paper pulp, in which the base is formedintegrally with the body of the vase, without the use of acore, andwithout sacrificing either stability or rigidity.

A further object is to provide an improved process for manufacturingpapier-mach vases which substantially reduces the cost of the article.

According to this invention papier-mach vases are produced from paperpulp in the usual manner on a mold formed of a fine mesh screen or wirecloth by drawing the pulp on the mold with suction applied to theinterior of "the mold, while it is immersed in the pulp. However,instead of using a single mold .and .a sand core for the .base, theprocess comprising the present invention utilizes two molds, one for thebody .of the vase, .and another for the base, eliminating the necessityof a sand core for the base. This 'is accomplished by first applyingpaper :pulp containing .a suitable binder to the two molds individually,the molds being separated from each other. After both molds havereceived 'a :layer of paper pulp, they are 'ice brought together whileimmersed in the pulp, with the body mold on top of the base mold, in thesame relationship as exists in the completed vase. Then an additionallayer of pulp is applied over the entire unit while the two molds are inposition to form a complete vase. When sufiicient pulp has been appliedto the molds they are removed from the pulp as a unit and the excessmoisture is drawn out of the pulp by again applying the suction to theinterior of the molds. Upon removing the excess moisture from the pulp,but while it is still damp, the molds are removed, as the pulp then hassufficient body to retain the shape into which it has been formed. Theyare then placed in an oven to be dried, and the completed article is asingle unit, the base being integral with the body of the vase.

The foregoing and other objects of the invention, which will becomeapparent from the following detailed specification setting forth anillustrative embodiment, may be achieved by carrying out the processwith the apparatus depicted in and described in connection with theaccompanying drawings, in'which:

Figure 1 is a view partly in front elevation and partly diagrammatic, ofapparatus provided for molding papiermach vases in accordance with theprocess of the present invention, with the molds being shown withdrawnfrom the pulp;

Figure 2 is a view in front elevation of the apparatus depicted inFigure 1, but with the molds immersed in the pulp and the hydrauliccircuit omitted;

Figure 3 is a view in vertical section taken along the plane representedby the line 3-3 in Figure 2, with the molds still immersed in the pulpbut the base mold and body mold drawn together to form a completed vase;

Figure 4 is a fragmentary view in front elevation of the apparatusillustrated in Figure 1, illustrating the molds withdrawn from the pulpafter a layer of pulp has been applied, the base mold and body moldbeing united;

Figure 5 is a fragmentary view in front elevation, substantiallyidentical to the view in Figure 4, except that the base mold has beenseparated from the body mold; and

Figure 6 is a perspective view of the completed vase removed from themolds.

Referring now more specifically to the drawings, there is shown aparticular apparatus especially adapted for carrying out the process ofthe present invention. The apparatus comprises a vat 11 for containing apaper pulp 12 to which a suitable binder has been added for the purposeof causing the mixture to form a rigid mass of substantial strength whendried, the resulting material being commonly known as papier-mach. Thepurpose of the illustrated apparatus is to enable the paper pulp to beformed into the shape of a vase which may be dried, to produce apapier-mach vase of simple but sturdy construction.

Above the vat 11 there are supported a plurality of unit molds 1-3 formolding the vases into the desired shape, the illustrated embodimentshowing four such molds, although it is to be understood that anyreasonable number may be provided, depending of course, on the amount ofproduction required. Each of the unit molds 13 comprises two individualmolds 1 5 and 15, the mold 14 being referred to as the body mold, sinceit forms the upper portion or body of the vase, While the mold 15 isreferred to as the base mold, as it forms the base of the vase.

The base molds 15 are mounted on a platform 16 while the body molds 14are suspended from a plate E7 in operating relationship to theirassociated base molds 15'. The platform 16, carrying the base molds 15.,is supported by four rods 18 which depend from a bracket '19, beingsecured thereto "by four connectors 20 fixed to the bracket 19 at itsrespective corners and having threaded engagement with the upper ends ofthe rods 18. The bracket 19 in turn is secured to the end of a pistonrod 21 to move with it for producing vertical movement of the base moldsin unison.

The base mold platform 16 is mounted for movement relative to the plate17, being maintained in proper alignment therewith by four sleeves 26,each of which is fixed to the plate '17 and is disposed about one of therods 18. With this arrangement the platform 16 may be moved relative tothe plate 17, but their associated base molds 15 and body molds 14respectively, will remain in proper alignment with respect to eachother. As best seen in Figure 3 the plate 17 is fixed to a U-shapedpiston rod 27 by a pair of brackets 28.

Vertical movement of the base molds 15 relative to the body molds 14 isachieved by fluid pressure directed into a cylinder 33 to move itscooperating piston 34, shown in Figure 3. The piston 34 is secured tothe piston rod 21 for moving the base molds 15. Movement of the entireassembly, including both the base molds 15 and body molds 14 as aunitary structure is effected by fluid pressure directed into a cylinder35 to move its cooperating piston 36 which is secured to the U-shapedconnecting rod 27. "Since it is necessary to effect movement of theentire assembly with the piston 36, the cylinder 33 for actuating thebase molds 15 is secured to the U-shaped piston rod 27 by any suitablemeans such as screws 37 so that it will move with it.

Fluid pressure for actuating the pistons 34 and 36 is obtained from apump 40 as shown in Figure l, which pumps fluid from a sump (not shown)through an intake pipe 41, and discharges the fluid into a pipe 42 fortransmission to a pair of manually operated valves 43 and 44. The valve43 serves to control the flow of fluid to the cylinder 33 for moving thepiston 34 in either direction. The fluid may be directed to the upperportion of the cylinder 33 for the purpose of moving the piston 34downwardly by pivoting a handle 45 in one direction to direct the fluidfrom the pipe 42 into a flexible tubing 46 which has communication withthe upper portion of the cylin der 33. At the same time the valve 43connects a flexible tube 47 to the sump through a pipe 48, the tube 47having communication with the bottom of the cylinder 33 so that theexhaust fluid from the bottom of the cylinder '33 may flow into the tube47, for transmission to the valve 43 and thence into the pipe 48 whichcarries it to the sump.

In like manner, the flow of fluid into the cylinder 33 may be reversedby manipulating the handle 45 in the opposite direction. In thisposition, the valve 43 directs the flow of fluid from the pressure pipe42 into the flexible tube 47 to the bottom of the cylinder 33 foractuating the piston 34 upwardly. At the same time the valve 43 connectsthe flexible tube 46 to the return line 48 to carry the exhaust fluidfrom the top of the cylinder 33 into the sump.

Fluid pressure for operating the piston 36 in the cylinder 35 iscontrolled by the valve 44, the direction of flow being changed bymanipulating a handle 52. Pivoting the handle 52 in one direction servesto direct the fluid pres sure into a flexible tube 53 which carries thepressure to the top of the cylinder 35 for urging the piston 36downwardly. The exhaust fluid then flows from the bottom of the cylinder35 into a flexible tube 54 to the valve 44 which connects the tube 54with a return pipe 55 connected to the sump.

Pivoting the handle 52 in the opposite direction serves to reverse thedirection of flow just described so that the pressure is directed fromthe pipe 42 into the flexible tube 54 for transmission to the bottom ofthe cylinder 35 to move the piston 36 upwardly. The tube 53 then becomesan exhaust line, being connected to the return line 55 by the valve 44so that the exhaust fluid from the top of the cylinder 35 is carried bythe tube 53 to 4 the valve 44 and thence to the return line to return:to the sump.

The flow of pressure from the pipe 42 is directed to the cylinders 33and 35 by the valves 43 and 44 by pivoting their respective handles 45and 52 in either direc tion from the position shown in Figure l. Thedrawing shows the handles 4-5 and 52 in their neutral position where thepressure flow from the pipe 42 is blocked and no fluid is reaching thecylinders 33 and 35. it is to be understood that the hydraulic circuitis also provided with pressure relief valves (not shown) for relievingexcessive pressure built up in the lines by the pump 40, such valvesserving to bypass the cylinders and direct the fluid from the pump 40back to the sump. With the valves 43 and 44 in the closed position asshown in Figure l, the entire output of the pump 40 is returned to thesump by these relief valves.

It will be noted from the drawings that the molds are fabricated of afine mesh screen or wire cloth in the area where it is desired to applythe paper pulp, and the openings of the vase, where no paper pulp is tobe applied, are represented by solid sheet metal, the entire interior ofthe mold being hollow. The paper pulp is applied to the mold by suctionwhile the mold is immersed in the pulp, the suction serving to draw thepulp against the wire cloth portion of the mold. When sufiicient pulphas been applied to the molds to form a vase they are withdrawn from thepulp, and the interior of the molds are then connected to a source ofair pressure, which functions to release the completed vases from themolds.

A partial vacuum is produced in the interior of the molds for drawingthe paper pulp upon their wire cloth portions by a vacuum pump which isconnected to a control valve 61 by a pipe 62 and to another controlvalve 63 by a branch line 64. The control valve 61 functions to connectthe vacuum pump 60 with the base molds 15 while the control valve 63operates to connect the vacuum pump with the body molds 14. The valve 61has communication with the base molds 15 through a flexible tube 65,which connects with a pipe 66 having branch lines 67 in communicationwith the interiors of the molds. The valve 63 in turn, connects with thebody molds 14 through a flexible tube 70 which connects with a pipe 71having branch lines 72 in communication with the interiors of the bodymolds.

The air pressure for releasing the completed vases from the molds isobtained from an air pump 75. The air pump 75 is connected to the valves61 and 63, which also control the vacuum, by a pipe 76 and a branch line77. Thus, the valves 61 and 63 serve to connect either the vacuum pump60 or the air pump 75 to the interiors of the molds. The valves areprovided with operating handles 78 and 79 which may be manipulated ineither direction from the neutral position shown in Figure 1. Bypivoting the handles 78 and 79 in one direction the vacuum pump 60 maybe connected to the interior of the molds, and by pivoting them in theopposite direction the air pump 75 may be connected to the interior ofthe molds, in both cases, the valves 61 and 63 directing either thevacuum or the pressure into the flexible tubes and respectively. Theoperating handles 78 and 79 of the valves 61 and 63 are shown in Figurel in their neutral position where all flow through the valves isblocked.

The process of forming the vases upon the molds may be clearly followedfrom the drawings in which the several views show the successivepositions of the molds as the paper pulp is applied to them to completethe vase. In Figure 1, the molds are shown in their starting position,withdrawn from the paper pulp 12 and the base molds 15 separated fromthe body molds 14. With the molds in this position, the handle 52 of thevalve 44 is manipulated to direct the flow of fluid pressure from thepump 40 to the upper portion of the cylinder 35 to force its cooperatingpiston 36 downwardly. The piston 36 moves theentire *moldassembly withit, so that the body molds 14, and the base molds 15, move downwardly asa unit, without changing their positions relative to each other, intothe vat 1 1 to become immersed in the paper pulp 12 as shown in Figure2.

With the molds immersed in the pulp, and the body molds 14 separatedfrom the basemolds 15 as depicted in Figure 2, the handles 78 and 79 ofthe valves :61 and 63 respectively, are manipulated to connect thevacuum pump 60 with boththebod-y molds 14'and the base molds 15 to applya suction to the interiors of the molds. The suction thus applied servesto draw the paper pulp onto the wire cloth portion of the molds. It hasbeen found advisable to release the vacuum to the interior of the moldsand reapply ,itseveral times while the molds are in this position tomore closely compact the pulp upon the molds and also to provide aheavier layer of pulp, the handles 78 and 79 being returned to theirneutral position when the operation is completed.

It will be noted that when the pulp is being applied with the body molds14 separated from the base molds 15, a layer of pulp is being formed onthe top of the base mold 15, and the bottom of the body mold 14. Thesetwo layers are to be subsequently united to combine integrally and formthe bottom panel of the vase. To accomplish this, the base molds 15 aremoved upwardly into contact with the bottoms of the body molds 14 asillustrated in Figure 3, by manipulating the handle 45 of the valve 43to admit fluid pressure into the bottom of the cylinder 33.

The fluid pressure in the bottom of the cylinder 33 forces itsassociated piston 34 upwardly which causes the base molds 15 to moveupwardly relative to the body molds 14 by reason of the constructionpreviously described, into contact with the bottoms of the body molds14. As the base molds 15 thus unite with the body molds 14, thecombination takes the form of the completed vase. It has been foundhowever, that the mere uniting of the base molds 15 with the body molds14 after they have received a layer of paper pulp is not suificient toform an integral structure of papienmach. It is necessary to applyadditional paper pulp to the molds While they are in the combinedposition as shown in Figure 3, to complete the vase and create a smoothappearance with sturdy construction,

Therefore, after the molds have been combined, the handles 78 and 79 ofthe valves 61 and 63 respectively, are manipulated to again connect thevacuum pump 60 with the interiors of the body molds 14 and the basemolds 15 to apply suction to their interiors and draw an additionallayer of pulp upon their wire cloth surfaces. At this point it is againpreferable to release the vacuum and reapply it several times as in thecase when the body molds 14 Were separated from the base molds 15. Afterthis operation is completed, a finished vase 80, as depicted in Figure6, is formed on the combined molds, the handles 78 and 79 being returnedto their neutral position.

The entire mold assembly is then removed from the paper pulp as a unit,by manipulating the handle 52 of the valve 44 to admit pressure to thebottom of the cylinder 35 and force its piston 36 upwardly. The piston36 moves the entire mold assembly out of the pulp with the body molds 14and the base molds 15 remaining united as shown in Figure 4. At thispoint, the paper pulp adhering to the molds is a wet mass having a highliquid content, and the excess moisture is removed therefrom by againmanipulating the handles 78 and 79 to connect the interiors of the bodymolds 14 and the base molds 15 to the vacuum pump 60. In addition toremoving the excess moisture from the pulp, the suction thus appliedwhile the molds are withdrawn from the vat 11, serves to more closelycompact the paper pulp upon the molds.

The next operation in the process is to remove "the base molds 15 fromthe vases. This is accomplished by first connecting the air pump 75 tothe interiors of the base molds 15 to form an air pressure within thebase molds which functions to force the paper pulp off of the mold. Theslightest separation of the paper pulp from the molds provides an escapefor the air so that the vases are not deformed in any way by theapplication of the air pressure to them. The handle 45 of the valve 43is then manipulated to direct fluid pressure from the pump 40 to the topof the cylinder 33. The pressure in the top of the cylinder 33 urges thepiston 34 downwardly which moves the platform 16 and its associated basemolds 15 with it, so that the base molds are moved away from the bodymolds 14, the paper pulp vases adhering to the body molds as shown inFigure 5.

After the base molds have been separated from the body molds as shown inFigure 5, a tray or other similar receptacle (not shown) may be placedover the base molds 15, under the body molds 14 to receive the completedvases 80. Upon placing the tray in position to receive the vases, thehandle 79 of the valve 63 is moved to admit air pressure from the pump75 to the interiors of the body molds 14. The application of airpressure to the interiors of the body molds 14 serve to clearly separatethe completed vases 80 from the body molds 14, the vases dropping uponthe tray which has been placed underneath them.

Although not completely dry, the paper pulp has been suflicientlycompacted upon the molds, and the excess moisture has been removed byvacuum as previously described, so that the vases have sufiicient bodyto hold their shapes after they have been removed from the molds. Thecompleted vases 80 then appear as shown in Figure 6. They are placed inan oven where they are thoroughly dried to form a papier-mach vase ofrigid and sturdy construction, the completed vase being very durable andable to withstand a great deal of abuse.

From the foregoing detailed description of an exemplary processrepresentative of the process comprising the present invention, and anillustrative apparatus for carrying out the process, it is apparent thata new and improved method has been provided for molding papiermacharticles having a narrow central portion, in which the entire article isformed integrally from two molds, eliminating the necessity of utilizinga sand core to form a portion of the article.

Although the illustrative embodiment of the invention has been describedin considerable detail for the purpose of making a full disclosure of apractical operative arrangement by means of which the invention may bepracticed, it is to be understood that various novel features of theinvention may be incorporated in other arrangements Without departingfrom the spirit and scope of the invention as defined in the subjoinedclaims.

The principles of the invention having now been fully explained inconnection with the foregoing description of embodying structure, Ihereby claim as my invention:

In an apparatus for forming a papier-mach article of unitary structurefrom two separate molds, a vat for receiving the paper pulp of which thearticle is to be formed, a piston and cylinder mechanism having aconnecting rod extending therefrom, a first support fixed to saidconnecting rod for movement therewith above said vat, a mold shaped toform one portion of the article mounted on said first support so that itmay be moved with the support into and out of said "at, a second pistonand cylinder mechanism mounted on said connecting rod for movementtherewith, a bracket connected to be moved by said second piston andcylinder mechanism relative to said first support, a plurality of rodssecured to said bracket, a second support attached to said rods formovement with said bracket, a second mold shaped to form the otherportion of the article and carried by said sec- 0nd support in alignmentwith the first mold so that it may be moved by said second piston andcylinder mechanism into combined relationship with the first mold forforming the completed article, and a sleeve placed about each of saidrods and secured to said first support for guiding the movement of saidrods and thereby the movement of said second support relative to saidfirst support for retaining the two molds in proper alignment, wherebythe first piston and cylinder mechanism serves to move both of saidsupports and their associated molds unitarily into and out of the vat byreason of the mounting of the second piston and cylinder mechanism onits connecting rod, and the second piston and cylinder mechanism servesto move the second support relative to the first support for moving themolds into combined relationship or for separating them.

References Cited in the file of this patent UNITED STATES PATENTSHubbard June 13, Fairbanks et a1. Nov. 19, Bushnell Nov. 6, Harvey Aug.23, Mason Aug. 30, Hall May 9, Chaplin Jan. 5,

FOREIGN PATENTS Germany May 22, Great Britain Apr. 13, Great BritainMar. 4,

